diff mbox series

[RFC,07/37] mm: add FAULT_FLAG_SPECULATIVE flag

Message ID 20210407014502.24091-8-michel@lespinasse.org (mailing list archive)
State New, archived
Headers show
Series [RFC,01/37] mmap locking API: mmap_lock_is_contended returns a bool | expand

Commit Message

Michel Lespinasse April 7, 2021, 1:44 a.m. UTC 
Define the new FAULT_FLAG_SPECULATIVE flag, which indicates when we are
attempting speculative fault handling (without holding the mmap lock).

Signed-off-by: Michel Lespinasse <michel@lespinasse.org>
---
 include/linux/mm.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 8ba434287387..021fdab5b721 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -434,6 +434,7 @@  extern pgprot_t protection_map[16];
  * @FAULT_FLAG_REMOTE: The fault is not for current task/mm.
  * @FAULT_FLAG_INSTRUCTION: The fault was during an instruction fetch.
  * @FAULT_FLAG_INTERRUPTIBLE: The fault can be interrupted by non-fatal signals.
+ * @FAULT_FLAG_SPECULATIVE: The fault is handled without holding the mmap_sem.
  *
  * About @FAULT_FLAG_ALLOW_RETRY and @FAULT_FLAG_TRIED: we can specify
  * whether we would allow page faults to retry by specifying these two
@@ -464,6 +465,7 @@  extern pgprot_t protection_map[16];
 #define FAULT_FLAG_REMOTE			0x80
 #define FAULT_FLAG_INSTRUCTION  		0x100
 #define FAULT_FLAG_INTERRUPTIBLE		0x200
+#define FAULT_FLAG_SPECULATIVE			0x400
 
 /*
  * The default fault flags that should be used by most of the
@@ -501,7 +503,8 @@  static inline bool fault_flag_allow_retry_first(unsigned int flags)
 	{ FAULT_FLAG_USER,		"USER" }, \
 	{ FAULT_FLAG_REMOTE,		"REMOTE" }, \
 	{ FAULT_FLAG_INSTRUCTION,	"INSTRUCTION" }, \
-	{ FAULT_FLAG_INTERRUPTIBLE,	"INTERRUPTIBLE" }
+	{ FAULT_FLAG_INTERRUPTIBLE,	"INTERRUPTIBLE" }, \
+	{ FAULT_FLAG_SPECULATIVE,	"SPECULATIVE" }
 
 /*
  * vm_fault is filled by the pagefault handler and passed to the vma's